Mikkel Rask got his breakthrough in the Danish 1st Division in 2001 playing for Randers FC, but when the club later earned promotion to the Danish Danish Superliga in 2004 and suffered relegation that very same season, Rask moved to Viborg FF to stay in the Superliga. In-all Rask got to play 91 games and score 10 goals at top-flight level for Randers FC and Viborg FF, before Viborg FF suffered relegation in 2008. Rask then signed with Turkish Süper Lig side Diyarbakırspor in 2009, which at first seemed like a good move. However, the Turkish club was in financial trouble, so Mikkel Rask soon left the club in January 2010 and returned to Denmark.
From 1 January 2017 he switches to AGF. The contract runs until the summer of 2018.